The Perfect Sample
by MechanicalRosebud
Summary: Someone is stealing underwear on the Normandy and Shepard has to find out when all of sudden his underwear gets taken too. This is a one-shot that will possibly become in a series and I try to keep the characters as true to themselves as possible!


Just a little fun short, smutty story for you Legion/Shepard(M) fans out there but don't want all that long ass plot like my other story! Enjoy and review please! This is more set in Mass Effect 2 and with all the companions when they had downtime. Besides, I can't get enough of that geth dominating Shepard smut and since there's so little I made more that and since it's NaNoWirMo(National Novel Writing Month) it gives me another excuse to pump this baby out! Hoorah!

As always I do not own these characters or anything from the ME universe! Just a fan who likes to see certain people(and geth!) bang!

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Leon Shepard sighed as he rubbed his forehead in response to a pulsating headache as he listened to his crew's complaints. Something had been going on and had all the crew on edge with mysterious. Mis-matched blue and green eyes trailed over the gathered crew.

"So let me get this straight," Leon had his arms firmly crossed as he was tempted to leave his spot, leaning on the metal frame of the conference room and was looking at the several pairs of eyes that were feverishly staring him down as the Commander took a heavy sigh.

"All of your various…undergarments have gone missing?" A conjoined nod was brought up as Leon shook his head in disbelief.

"We have a panty burglar, Shepard." Garrus's voice was bordering on laughter as Leon shot him a harsh glare and waved his hand defensively, "So what should we do about this nefarious thief of underwear?" The turian couldn't help chuckle at his own phrasing before coughing to cover it up as he still trembled in holding any more laughter back.

"It's probably scale-itch over there! I don't see how this funny!" Jack practically growled as she shot Garrus a nasty glare that only got a mildly humored glance from the turian who shrugged as he threw his hands up when the other females of the crew looked his way.

"I don't have any use for those kind of undergarments turians have no need for that sort of clothing." Garrus said plaintively and then gave a shrug as the eyes fell away from him going back to Shepard who seemed just as amused about it as Garrus did.

"We don't care how you solve this problem, Shepard! Just solve it!" Leon mimicked Garrus's response as he threw his hands up and nodded slowly, "I'll make sure to take care of the panty bandit." Another throaty chuckle was cut off as a sharp jab with an elbow silenced the turian. After expressing their distress, the crew left as Shepard was left to ponder, in all seriousness, why only the females were having their panties taken? Maybe one of the male Cerberus crewmembers was having a bit of fun? He would have pinpointed Joker but with the pilot's condition he wouldn't be able to move around quick enough to be unseen.

Shaking off the thoughts, Shepard went down to the AI core he had started having daily conversations with the geth, Legion. It was helping both Shepard understand how the synthetics thought and helped Legion gather data for organic behavior. It was the majority of Shepard's reasoning along with the fact it was the only thing he could talk to without having some sort of back-handed questioning or comment. Even Garrus, who usually took the time to listen, had an occasional back-handed compliment or suggestion in his tone. Sometimes, Shepard just wanted the chance to talk without being questioned.

"Greetings, Shepard-Commander." Legion's mechanical voice came immediately as soon as Leon stepped through the doors and he nodded in acknowledgment.

"How are things, Legion?" It was always strange trying to make small talk but Legion never seemed to take heed, mostly likely since he wasn't organic.

"We have processed 3,546 strategies and simulations for better combat maneuvers to situate Shepard-Commander's unique combat actions." Shepard took a moment to take it in before he chuckled at Legion's terminology, "So you've been thinking of ways to adjust your fighting to my own?" Legion nodded sharply, "Correct." The geth always seemed to just be lingering in the AI core, never going anywhere or needing to do anything. Just lingering in that one spot.

"Well, can never be too prepared I appreciate your efforts to make things smoother, Legion." The geth nodded slightly and surprised Leon when it stepped closer as it made a strange dipping motion curving up toward him.

"Your facial motions are hinting at stress and contemplation, Shepard-Commander, may we assist?" The odd bending of the geth's body as it was leaned downward and curved toward him, making Legion appear to be looking up at him from below Leon was baffled by the fluid motion.

"Ah, that reminds me," he attempted to avoid looking at the oddly feline like curve it gave the geth's body making it seem more inticing, "apparently we've had some crew members'…undergarments go missing do you know anything about it?" Legion pulled back sharper than Leon realized the geth could move as it took it's upright position again now seemingly taking a minute longer than necessary to process the information.

"Undergarments? Clothing worn under the outer clothing?" Shepard felt a bit sheepish having to explain the mechanics of underwear to the geth but he nodded, "Yeah, something like that it's used to…give extra protection to the groin area of organics or at least for modesty." Shepard inwardly groaned at the curious tilt of Legion's head, meaning he wasn't completely sure of what Shepard meant.

"Modesty is an organic feeling of being private or being protective of personal things like cleanliness." Leon Shepard wasn't exactly sure how he was going to explain modesty and underwear in detail to Legion. He was hoping the geth would drop it but of course Legion couldn't sense those kind of things.

"We would like a more in-depth description of various human customs and emotions." Shepard sighed deeply inwardly as he gave a slow, almost automatic nod as he moved to sit on the berth at the back of the AI core as Legion moved closer to hear him better, he guessed. "Alright, let me explain this the best way I can…" Leon Shepard went into as much detail as he could to explain how organics felt modesty and needs for privacy around others, friends or others alike. Needless to say it was a lengthy back and forth that left the poor Commander exasperated with the effort.

"The basis of organic sense of modesty is based from the need of privacy from other organics?" Legion seemed to get the hang of it and Leon nodded slowly, not wanting to hope for an understanding that wasn't there. The geth looked down briefly, "We appreciate, Shepard-Commander's willingness to aid us in understanding the organic mindset more thoroughly." Legion did that strange curved leaning once more toward Shepard, the man couldn't help but notice that attractive spinal curve once more. Briefly, he envisioned his hands sliding down those cables and smooth metal frame. The rush of heat brought him back to his senses as he quickly moved off of the berth, bumping into the geth as he murmured an apology before moving. The close proximity, despite how brief it was, had been stimulating especially with the feel of the cold metal against him.

"I should go." Leon gave his usual words before he departed and the geth nodded in understanding, "We understand our inquiry was lengthier than usual, and we look forward to future exchanges with you, Shepard." Leon didn't noticed the change of his name from Legion until much later, after he had managed to cool down from the strangeness of their encounter.

Legion watched as Leon Shepard's form disappeared as he walked out of the doors of the AI core, the geth turned back toward the berth as it bent taking a box from below. Taking a moment to look at the simple box, the geth looked inside of it briefly before it putting it away again running more simulations in its processors to calculate the different percentages of success. The geth realized it needed to do more research before coming to a consensus.

"Perfect sample needed for further research and data compilation." After having briefly gone through the box's contents Legion concluded that no sample within would give the results it was looking for. Time to start anew and this time the geth had an idea where to look.

"This can't be happening…"Leon irritably rubbed his forehead for less amusing reasons than the ones he had heard a week ago. He had never figured out who had been stealing the crew's underwear but now his own was going missing! It seemed that it was only his own that was starting to vanish these days with the others having theirs mysteriously returned. It was all odd but now he was simply frustrated that he didn't have any of his own.

It was an embarrassing problem and there wasn't any way the Commander was going to bring this up to the crew. They would be laughing for weeks, months even if they even suspected something like this was going on though it was still a disturbing thought knowing one or more of the crew was stealing his underwear. Couldn't the Normandy and crew ever have any regular problems? Panty-theft, he didn't think, wasn't a usual problem. He even felt strange using that terminology and sighed as he dressed without the usual barrier of boxers to keep the leather from rubbing him raw against his own hip seems he would just have to get through it.

It took a couple more days before Leon Shepard started to lose his temper about it and spoke to EDI if she had seen any strange activity on the ship. The AI had replied negatively but, curiously to Shepard, she held a slight suspect tone to her voice. He let it slide though EDI didn't have any motives to hide anything suspect from him.

"Shepard-Commander we wish to speak with you." Leon looked up from the galaxy map he was examining toward the geth who approached the man once it had been acknowledged. Shepard took a long moment, noticing the box the geth was holding, before nodding slowly as the geth shook its head. "We wish to speak privately." Leon was interested now, "Alright, come with me to my quarters." Legion stepped into the elevator with Shepard.

"Alright, what did you want to talk about, Legion?" Leon Shepard turned as Legion moved forward and handed Shepard the box, "We have managed to collect a sample with help from your articles of clothing." Leon blinked as he thought on what the geth said before opening the box and seeing a pair of blue, silk boxers folded neatly on a pile of several other pairs he had been missing. His anger at the situation turned into a mortified curiosity.

"Wait…why do you need a sample and why did you take my underwear?" Shepard was baffled. He had expected someone was taking his boxers but Legion had been the farthest from all of those guesses. The geth ducked its head before making that strange, curved motion again and it sent shivers down Shepard's spine at the smooth bent angle of the geth's back leading to its hips.

"We are pleased you have inquired." Legion made the most graceful motions Shepard thought was impossible for the geth as it moved closer to him and the man felt the gentlest touch raise the hairs on his arms. He didn't realize he had made soft gasping sounds until the pressure of hands squeezing his arms came to the fore-front of his mind and it took even longer, longer than he'd admit, to notice the geth was walking him backwards toward his bed.

"We wished to engage, Shepard-Commander in an intimate setting and the gathering of aromas was needed to create the perfect sample." Leon Shepard managed to hear the words but found himself staring firmly at the solid blue optic and the shuddering face plates that seemed to mimic the delicious thrills tingling over his skin. The sudden feel of the edge of his bed, Shepard glanced at it for a moment before turning back to the synthetic who was oddly silent.

"Shepard-Commander is less hostile and data suggests the optimal path of stress relief is to engage in vigorous physical activity." Leon wasn't sure what surprised him more the fact that Legion knew how to undress him from the many buckles and zippers along his uniform or that he didn't seem all that adverse to it. A part of him sighed about how nothing normal happens on the Normandy it brought a small chuckle to his lips.

"Sex is the optimal course of action to both relieve Shepard's continued state of hyper-stress and provide us with data of organic interaction." Leon shuddered at the bitingly cold air against his hot skin and once more was surprised at his rather docile reaction to what was going on as the geth gently pushed him back onto the bed.

"You are subdued from the perfect sample, the aroma we have created has responded to your basic instincts and desire to copulate therefore rendering you complacent." Leon felt he didn't care about why or how it was happening but wanted it to happen. Now. Scratch that, not now, but right now. Naked and shivering eagerly, Shepard willingly opened his arms to Legion who slid into his arms as he moaned at the violate contrast of hot flesh pressing into cold metal twisted into fibers. Shepard couldn't remember the last time he'd even considered having sex and certainly hadn't imagined he'd break his dry spell fucking a geth named Legion.

Legion took control immediately pinning the man's wrists above his head and straddling a naked waist, as fingers mercilessly prodded pressure points weaving a plethora of moans out of its victim. Letting go of Shepard's wrists, Legion stroked shapely sides as he moaned and almost screamed as fingers pinched reddened nipples. The geth took it all in memorizing the contours of Shepard's face in pleasure both willing and unwilling.

"Fuck, Legion…stop teasing me," Shepard whined, the fleeting touches only agonizing him as he reached up stroking the geth's thighs and a spark of electricity surprised both with a charge. Shepard purred at the gentle shaking that rocked Legion's frame and he let his hands move over the carefully made limbs. Legion slowly stroked the taunt sides analyzing data it had found via extranet to pinpoint the man's various points of pleasure. The geth felt it was succeeding with the barely held-back whimpers.

Memorizing the Commander's body it calculated where all the various points would be and attacked with intent finding that it was enjoying the screams of pleasure from an over-stimulated nervous system. Shepard jerked wildly under its prodding and bucked as Legion dug hard bumping the bone on Shepard's hips as the man sobbed pitifully desperate for release but not admitting it.

"You are very stressed, Commander. Allow us to relieve you." Metal fingers roughly pinched abused nipples as Shepard squirmed to escape the delicious agony whimpering as the geth pinched harder. Legion took it all in, the hooded dark eyes and finely coating sweat over his body, as the man arched his spine to the sharp tug.

Leon Shepard was eagerly enjoying the attention as he hissed the abuse on his chest was enough to drive him insane and felt a gaping sense of loss as he felt it stop. After a few seconds, Leon opened his eyes to see Legion no longer even on the bed but watching him intently standing at the foot of the bed.

"Why did you stop?" Shepard quickly felt a growing longing for more contact as he sat up, noticing briefly his hair was down by the white in the corner of his vision, and looked back at Legion to notice his blue hairband on the geth's wrist.

"We have collected the optimal sample from Shepard-Commander and wish to study it further before completing our research." Leon sighed at the geth's words, figuring that it meant before he would get any action Legion wanted to perfect whatever it was doing. Legion noticed the decrease of stimulation and rather depressive mood that seemed to settle over the Commander.

"Do you wish for us to continue and allow you to reach culmination?" Shepard was only partially surprised by Legion's question and sighed at the still stiff erection between his thighs, the pleasure was ebbing but unless he wanted to be uncomfortable for the rest of the day. As soon as Shepard gave a nod he almost leapt out of his flesh at the cold metal wrapping around his cock, hissing he was surprised how quickly Legion retook his position above the Commander. Quickly throwing an arm around the geth as it jerked hard moving its hand squeezing tight as Shepard screamed at the sudden assault, his body bowed instantly hips jerking futilely to the harsh motion. Nails dragged hard against metal plates that screeched in protest.

Legion took the shotgun fast response of Shepard's almost beastial growls, optic widened in observation taking data as it adjusted speed, grip and even angle, turning it slightly made the man below open slitted eyes showing signs of elevated lust. The geth was snapped out of its close observation when Shepard, still struggling to hold onto himself, took the geth's free hand leading it further between his legs brushing the wrinkled flesh caused the man to moan with a violent shudder.

It took only a few seconds for the geth to process the Commander's intention, "Affirimative, Shepard." Leon whined as Legion slowed the pace as it switched hands giving the slick cock a squeeze, Shepard relaxed a bit and gave off soft moans with Legion's gentler and slower pace, the three fingers evoking magic along the Commander's straining cock. The three fingers rubbed and put pressure on all the right spots, Leon couldn't even think clearly just watching those fingers move on him was fucking magic.

"Fuck, Legion you've been…studying human anatomy." Saliva ran down the corners of Shepard's mouth, only more evidence to Legion of his arousal as the geth pinched the base earning a sharp yelp not entirely of pain before teasing the slit on the head a quick thrust was his response to the prodding. "We have been examining your anatomy with accordance of generalized human pleasure and pressure points." Leon hissed feeling a slick finger push inside, probing gently and rubbing at clenched muscle.

"Wha~" Shepard broke off into a scream, spine arching off the bed as Legion felt his system overheat, the data overwhelming and copious as the geth concluded it was time to collect the final piece. The geth mercilessly thrust against the sensitive bundle of nerves sending Shepard into a flurry of screams and wild thrashing at the onslaught of razor-sharp pleasure on his body. Leon Shepard had never experienced such a viciously painful pleasure but found himself more than eager to take it when it was being given. Legion simultaneously increased its hand, gripping tightly and twisting Shepard's cock in a painful arch, it only drove the man more insane hips bruised from slamming into the geth's.

Shepard thrust wantonly on the fingers jamming into his stretched hole as he tore his sheets and held onto Legion as he arched harder feet slipping on the bed. "LEGION!" Realizing Shepard was dangerously close to orgasm, Legion slammed its hand almost completely in sending the man into a mind-shattering orgasm as he screamed slamming into the geth above him before he collapsed back onto his bed breathing harder than the geth had ever seen him. The geth curiously noted, the thick globs of fluid on its hand and spattered on its body.

"Have we aided in Shepard's stress relief?" Leon cracked open a light colored eye and couldn't help but smile slightly at the geth as he nodded, "Yes, very much so." Legion's faceplates moved excitedly as Leon felt tings of amusement at the geth's reaction as he gasped when Legion pulled its hand out, shuddering at the residual pleasure washing over him. Leon Shepard had a lot of questions but he was too damn satisfied to give a shit, at least in his post-orgasm it had been so long since he had enjoyed that kind of pleasure. A small slot in Legion's chest opened as the geth took out a small container and, much to Shepard's curiosity, collected the semen from their intimate moment.

"Why are you doing that?" Shepard was feeling satisfied and ready to curl into his sheets even as he spoke he was slipping under them. Legion tilted its head at him curiously before climbing back onto the bed, gently bumping its faceplates on Shepard's cheek before earning a yip with a flick to over-sensitive nipples. "We are always collecting data. You have given up the perfect sample." Shepard blinked and felt his cheeks burn a bit with color as he rubbed the back of his head nervously, "You're welcome?" Shepard was sure if Legion could laugh it would be doing so by the air between them.

"Ah, and thank you, Legion." The geth's faceplates shuddered, "We only wish to aid you, Shepard and to keep up you at maximum efficiency." The Commander smiled, though the words were harshly technical, he thought it was sweet and patted the bed. "Stay with me hm? It's probably cold in the AI core anyway." Legion seemed to weigh the options, "We do not feel 'cold' but we are getting the idea you prefer the delicacies of intimacy after coitus. We will oblige." Shepard smiled and made room as the geth put the collected sample back into its chest. Legion crawled onto the bed and faced toward Shepard as they had to figure a position that wouldn't be so strange for either of them. After some awkward shuffling, Legion ended up with its head tucked under Shepard's chin, arm on his side and legs slightly mixed together.

"We would like to thank you, Shepard for allowing us to collect data and engaging in experimentation." Shepard chuckled and the Commander gently placed kisses on the shuddering faceplates as he stroked the curved head lovingly. "You're welcome, Legion." The lights dimmed to allow sleep even as the geth's optic glowed still but also dimmed in preparation stages of recharge.

"Would Shepard-Commander allow further experimentation and data collection?"

"Of course but you never explained why you were collecting underwear, Legion."

"We were collecting data and samples from the crew."

"Yeah, but why?"

"….No data available." There was an audible, exasperated sigh in the darkness of the bedroom.


End file.
